Effects of diquat and fomasen applied alone and in combination with a nonylphenol polyethoxylate adjuvant on Lemna minor in aquatic indoor microcosms - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Ecotoxicology and Environmental Safety Année : 2009

Effects of diquat and fomasen applied alone and in combination with a nonylphenol polyethoxylate adjuvant on Lemna minor in aquatic indoor microcosms

Résumé

The influence of tank-mix adjuvants on pesticide toxicity remains largely unknown. Agral® 90, a nonylphenol polyethoxylated tank-mix adjuvant, has been used with diquat (bipyridylium herbicide) and fomesafen (diphenyl-ether herbicide) in aquatic indoor microcosms in order to compare the toxicity of the single compounds and of binary herbicide–adjuvant mixtures to Lemna minor. Twenty-four microcosms were used and treatments were performed with substances alone or with herbicide–adjuvant binary mixtures, at two concentrations levels (44.4 and 222.2 μg/L for the herbicides, and 100 and 500 μg/L for Agral 90). Toxicity was assessed weekly for 1 month through growth measurements, as inferred from the relative frond number (RFN) and relative frond area (RFA). Concentrations of diquat and fomesafen in water and sediments were measured weekly. The herbicides showed very different behaviour in microcosms, with a rapid disappearance of diquat from the aqueous phase whereas fomesafen levels remained almost constant over time. Diquat strongly inhibited the growth of L. minor whereas fomesafen had no effect on plant growth. Presence of the adjuvant only slightly reduced the effect of the lowest concentration of diquat, probably as a result of dispersion of the herbicide at the water surface. It is concluded that tank-mix adjuvant designed to improve herbicide efficiency in the terrestrial environment did not have any effect on aquatic plants when applied to the aquatic environment.

Dates et versions

hal-01453751 , version 1 (02-02-2017)

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Caroline Gorzerino, Alphonse Quémeneur, Anne Hillenweck, Maryse Baradat, Georges Delous, et al.. Effects of diquat and fomasen applied alone and in combination with a nonylphenol polyethoxylate adjuvant on Lemna minor in aquatic indoor microcosms. Ecotoxicology and Environmental Safety, 2009, 72 (3), pp.802-810. ⟨10.1016/j.ecoenv.2008.08.001⟩. ⟨hal-01453751⟩
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